Table of standard reduction potentials for half-reactions important in biochemistry

The values below are standard reduction potentials for half-reactions measured at 25°C, 1 atmosphere and a pH of 7 in aqueous solution.^[1][2]

Half-reaction	Δξ°'(V)	E' Physiological conditions	References and notes
CH3COOH + 2 H^+ + 2 e^− → CH3CHO + H2O	-0.58
2 H^+ + 2 e^− → H2	-0.42
NAD^+ + H^+ + 2 e^− → NADH	-0.320	-0.280	The ratio of NAD^+:NADH is maintained at around 30:1.[3] This allows NAD^+ to be used to oxidise organic molecules
NADP^+ + H^+ + 2 e^− → NADPH	-0.320	-0.370	The ratio of NADP^+:NADPH is maintained at around 1:50.[3] This allows NADPH to be used to reduce organic molecules
FAD + 2 H^+ + 2 e^− → FADH2 (coenzyme bonded to flavoproteins)	-0.22		Depending on the protein involved, the potential of the flavine can vary widely[4]
O2 + 2 H^+ + 2 e^− → H2O2	+0.30
O2 + 4 H^+ + 4 e^− → 2 H2O	+0.82
P680^+ + e^− → P680	~ +1.0

Notes

References

1. Berg JM, Tymoczko JL, Stryer L, (2001) Biochemistry, 5th edition, WH Freeman, New York
2. Voet D, Voet JG, Pratt CW, (2013) Fundamentals of Biochemistry, 4th edition, John Wiley & Sons, New York
3. Huang, Haiyan; Shuning Wang; Johanna Moll; Rudolf K. Thauer (2012-07-15). "Electron Bifurcation Involved in the Energy Metabolism of the Acetogenic Bacterium Moorella thermoacetica Growing on Glucose or H2 plus CO2". Journal of Bacteriology 194 (14): 3689–3699. doi:10.1128/JB.00385-12. ISSN 0021-9193. Retrieved 2013-09-10.
4. Buckel, W.; Thauer, R. K. (2013). "Energy conservation via electron bifurcating ferredoxin reduction and proton/Na+ translocating ferredoxin oxidation". Biochimica et Biophysica Acta (BBA) - Bioenergetics 1827 (2): 94. doi:10.1016/j.bbabio.2012.07.002.